Image forming apparatus having a blocking member that changes a width of an opening of an air blow portion

Abstract

An image forming apparatus includes a fixing device having a nip, in which an image is fixed on a recording material, and an air blowing unit configured to feed air. A first blow portion is provided, through which the air fed by the air blowing unit flows toward a first area, which is an end portion of the fixing device, in a longitudinal direction of the fixing device, so as to cool the first area by the air via an opening of the first blow portion. A blocking member changes a width of the opening of the first blow portion, and a second blow portion is provided, branched from the first blow portion so as to cross the first blow portion, through which the air blocked by the blocking member flows toward a second area, which is a region in which the recording material passes through the nip.

What is claimed is: 
     
       1. An image forming apparatus comprising:
 an image forming portion configured to form an image on a recording material; 
 a fixing device having a nip, and configured to fix the image on the recording material while nipping and feeding the recording material on which the image is formed; 
 a cooling fan configured to feed air; 
 a first blow portion through which the air fed by said cooling fan flows toward a first area, which is an end portion of said fixing device, in a longitudinal direction of said fixing device, so as to cool the first area by the air via an opening of said first blow portion; 
 a blocking member configured to change a width of the opening of said first blow portion; and 
 a second blow portion, branched from said first blow portion so as to cross said first blow portion, through which the air blocked by said blocking member flows toward a second area, which is a region the recording material passes through said nip. 
 
     
     
       2. The image forming apparatus according to  claim 1 , further comprising an air feeding path from said cooling fan to said first blow portion. 
     
     
       3. The image forming apparatus according to  claim 1 , wherein the second area is in a central region in the longitudinal direction. 
     
     
       4. The image forming apparatus according to  claim 1 , wherein said blocking member changes the width of the opening of said first blow portion in accordance with a length, measured in a widthwise direction, of the recording material. 
     
     
       5. The image forming apparatus according to  claim 1 , wherein said fixing device includes a fixing member,
 wherein said apparatus further comprises a thermistor configured to acquire information of a temperature of said fixing member, and 
 wherein said blocking member changes the width of the opening of said first blow portion in accordance with an output of said thermistor. 
 
     
     
       6. The image forming apparatus according to  claim 1 , wherein, in the longitudinal direction, a cooling region of the recording material cooled by the air from said cooling fan is greater than a non-cooling region of said fixing member not cooled by the air from said cooling fan when said blocking member does not change the width of the opening of said first blow portion. 
     
     
       7. The image forming apparatus according to  claim 1 , further comprising a third blow portion through which the air from said cooling fan flows toward the second area so as to cool the second area regardless of the position of said blocking member, wherein, in the longitudinal direction, said second blow portion is located further outward from a center of said fixing device than said third blow portion.